Laparoscopy requires the insufflation of pressurized gas into the abdominal cavity to create a surgical workspace. Higher insufflation pressure results in a larger workspace, but the abdominal cavity wall allows limited stretch, with decreasing volume gains per pressure increment. The relationship between pressure and volume is defined as compliance and varies between patients. Clinically, there is no method to assess quantitative feedback on patient-specific abdominal compliance. Therefore, there is a risk of applying unnecessarily high pressures for the creation of a sufficiently large workspace, impairing ventilation and organ perfusion, and resulting in more postoperative pain. Providing quantitative feedback could reduce the negative effects of pressurized gas insufflation. A method for non-invasive monitoring of abdominal compliance during minimal access surgery could be found in the forced oscillation technique. Erasmus MC (Rotterdam, NL) and Politecnico di Milano (Milan, IT) have validated this Endoscopic Forced Oscillation Technique (EndoFOT) in an animal model. The next step was to integrate the technology into a medical device. This medical device required a Graphical User Interface (GUI) with presenting real-time estimations of abdominal compliance. In this Thesis study, a GUI and real-time algorithm was developed and tested. Effectiveness and ease of use were proven by means of formative Human Factors test. The real-time estimation algorithm was tested and validated in-vitro, providing accurate and reliable results. Further in-vitro experiments and data analysis were carried out to evaluate the effects of mechanical ventilation on the EndoFOT technology.
La laparoscopia richiede l’insufflazione di un gas pressurizzato nella cavità addominale per creare uno spazio di lavoro chirurgico. Una maggiore pressione di insufflazione crea un maggiore spazio chirurgico, ma la parete addominale permette un’espansione limitata, con incrementi di volume sempre minori all’aumentare della pressione. La relazione tra pressione e volume è definita come compliance e varia in base al paziente. Clinicamente, non esiste alcun metodo che provveda un feedback quantitativo sulla compliance addominale dello specifico paziente. Esiste quindi il rischio di applicare pressioni più alte del necessario per la creazione di spazio di lavoro chirurgico sufficientemente spazioso, così compromettendo la ventilazione e la perfusione degli organi, nonché risultando in un maggior dolore post-operativo. Un feedback quantitativo potrebbe ridurre gli effetti negativi dovuti all’insufflazione del gas pressurizzato. La tecnica delle oscillazioni forzate potrebbe essere un metodo non invasivo per il monitoraggio della compliance addominale durante la chirurgia laparoscopica. Erasmus MC (Rotterdam, NL) e Politecnico di Milano (Milan, IT) hanno validato la Endoscopic Forced Oscillation Techinique (EndoFOT) su un modello animale. Il passo successivo è l’integrazione della tecnologia su di un dispositivo medico, il quale richiede un’interfaccia grafica (GUI) che possa presentare stime della compliance addominale in tempo reale. Con questa tesi si è sviluppata la GUI e rispettivo algoritmo real-time. Uno studio formativo di usabilità ne ha dimostrato l’efficacia e la facilità di utilizzo. L’algoritmo real-time è stato testato e validato in-vitro, fornendo risultati accurati e affidabili. Ulteriori esperimenti in-vitro e analisi dei dati sono stati effettuati per valutare gli effetti della ventilazione meccanica sulla tecnologia EndoFOT.
A novel device based on forced oscillation technique for tailoring intra-abdominal pressure during laparoscopy
Gimignani, Veronica
2019/2020
Abstract
Laparoscopy requires the insufflation of pressurized gas into the abdominal cavity to create a surgical workspace. Higher insufflation pressure results in a larger workspace, but the abdominal cavity wall allows limited stretch, with decreasing volume gains per pressure increment. The relationship between pressure and volume is defined as compliance and varies between patients. Clinically, there is no method to assess quantitative feedback on patient-specific abdominal compliance. Therefore, there is a risk of applying unnecessarily high pressures for the creation of a sufficiently large workspace, impairing ventilation and organ perfusion, and resulting in more postoperative pain. Providing quantitative feedback could reduce the negative effects of pressurized gas insufflation. A method for non-invasive monitoring of abdominal compliance during minimal access surgery could be found in the forced oscillation technique. Erasmus MC (Rotterdam, NL) and Politecnico di Milano (Milan, IT) have validated this Endoscopic Forced Oscillation Technique (EndoFOT) in an animal model. The next step was to integrate the technology into a medical device. This medical device required a Graphical User Interface (GUI) with presenting real-time estimations of abdominal compliance. In this Thesis study, a GUI and real-time algorithm was developed and tested. Effectiveness and ease of use were proven by means of formative Human Factors test. The real-time estimation algorithm was tested and validated in-vitro, providing accurate and reliable results. Further in-vitro experiments and data analysis were carried out to evaluate the effects of mechanical ventilation on the EndoFOT technology.| File | Dimensione | Formato | |
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https://hdl.handle.net/10589/173241